Helicopter steering surface control



Mmh E. L. KIRCHOFF 7,

HELICOPTER STEERING SURFACE CONTROL Filed Feb. 16, 1945 2 Sheets-Sheet lMuch 1948. E'. L. KIRCHOFF 1 2,437,324

HELICOPTER STEERING SURFACE CONTROL Filed Feb. 16, 194 5 2 Sheets-Sheet2 Patented Mar. 9, 1 948 UNITED STATES PATENT OFFICE HELICOPTER STEERINGSURFACE CONTROL Elden L. Kirchoflr, Hawthorne, Calif.

Application February 16, 1945, SerialNo. 578,144

6 Claims. 1

This invention relates to helicopters of the type in which vanes locatedin the slipstream of the gondola-sustaining rotor are adjustable tointercept the slipstreamat different angles to thereby impart anunbalanced force to the gondola about its longitudinal axis and allowdirectional control of the helicopter while it isin flight. One suchtype of helicopter is shown in the patent-of Yern Keith Fry, No.2,058,678, dated October 27,

An important object of my invention is to provide in a helicopter of theabove character vanes of improved construction and arrangement, wherebyto more efiiciently utilize the air currents generated by the rotor fortilting the helicopter during flight.

Another object of my invention is to provide in a helicopter of theabove character control means of improved construction and arrangementfor varying the angular adjustment of the vanes for steering thehelicopter while in flight.

Still another object of my invention is to provide in a helicopter ofthe above character improved control means for varying the angularadjustment of both the vanes for directional control and the blades foropposing the torque developedby the rotor, such. control means beingassociated with a single control stick conveniently located withreference to the pilot.

Other objects and advantages will be apparent from the followingdetailed description of the invention, reference being had tothe annexeddrawings, in which:

Figure. 1 is a side view ofa helicopter having its longitudinal axisdisposed vertically, showing its position when on the ground or indirect vertical flight;

Figure. 2 is a detail view of the control stick, parts. thereof beingshown in cross-section for greater clearness;

Figure 3 is a detail view of one of the stabilizing blades and itscompanionsteering vane, showing the manner in which they are associatedwith each other and with the gondola of the helicopter; and

Figure 4 is a perspective view, mainly diagrammatic, showing the controlmechanism for adjusting. the positions of the blades and vanes abouttheir axes.

Referring to the drawings, in Fig.1 is shown a helicopter comprising adownwardly and outwardly flared gondola I of generally teardrop shapehaving its longitudinal axis disposed Vertically and terminatingat itsupper smaller end in a tapering neck 2. Through this neck and fixedlysupported in line with the longitudinal axis of the helicopter, extendsa driven shaft 3 (indicated in dotted lines) upon the upper projectingend of which is secured a rotor 4 com prising a plurality of blades 4a.The shaft 3 is coupled to and driven by a motor 5, such as an internalcombustion engine, mounted within the neck of the gondola with itscylinders projecting therefrom into the slipstream of the rotor topromote theircooling. Within the area of the neck below the motor arecontained oil and fuel tanks, designated 6 and 7 respectively, forsupplying the motor. A floor 8 extends across the gondola sufiicientlyfar below the fuel tank to afford space for a passenger cabin 9 in whichare provided chairs [0, instrument panel II and steering control memberl2 known as a stick. The floor is disposed at a downward slope withrespect to the horizontal from the front (that is, the direction facedby the pilot in operating the stick 12) to the rear wall of the cabin,so that when the helicopter is in flight with its longitudinal axisnormally tilted forward the floor will assume an approximatelyhorizontal position. The space below the floor 8 forms a compartment Itfor the stowage of cargo, access being provided to this space through adoor It. A window l5, made of Plexiglas or the like material, entirelyencircles the gondola throughout an appropriate distance above the seatlevel to afford visibility in all directions. For providing admission toand exit from the cabin 9, to a door I6 is mounted in the rear wall ofthe gondola. A tricycle landing gear H, which may or may not beretractible, and comprising wheels 18 mounted upon oleo struts [9,supports the helicopter on the ground with its longitudinal axisextending substantially vertically.

In order to offset the torque imparted to the gondola-by the rotation ofthe rotor when the helicopter is in flight, which torque tends to turnthe gondola about its longitudinal axis in a direction opposite to therotation of the rotor, there are provided four generally rectangularshaped blades 20; The blades, as best illustrated inFig. 3, are fixedlymounted upon hollow tubular shafts 2| extending horizontally outwardthrough the wall of the gondola at equidistantly spaced points about itsgirth, These shafts lie within a common plane disposed at right-anglesto the longitudinal axis of the gondola and intersecting the gondola ator adjacent to its maximum diameter. The blades are so arranged as toextend into the slipstream of the rotor 4 and act as stabilizers toneutralize the. torque produced by the rotation of the rotor. By rockingthe shafts 2|, the angle of interception of the blades may be adjustedto offset changes in torque such as may result from variations in thespeed of the rotor or due to other factors. In order to operate mosteffectively, the blades are of substantial length and breadth so as topresent an adequate deflection area to the slipstream, with their inneredges spaced a short distance from but corresponding in contour to thecurved exterior face of the gondola.

Arranged outwardly of and in laterally-spaced relation to the blades 28are rectangular vanes 22 which serve to provide directional control forthe helicopter when in flight. These vanes, which may be of less lengthand breadth than the blades since they are not required to present somuch area to the slipstream, are mounted upon the outer ends of shafts23 (Fig. 3) which fit within and project beyond the outer end of thehollow shafts 2!. The shafts 2! and 23 are capable of being rocked abouta common axis independently of each other, and to this end the followingoperating mechanism is provided: Inside the gondola each shaft 2| isprovided with an arm 24 connected to a cable 25 winding over pulleys 25rotatably supported on the wall of the gondola in such a manner that thecable extends in out-- of-the-way position with respect to the passengerspace of the cabin. By moving the cable in one or the other directions,the blades 26 are swung in unison in the same clockwise orcounter-clockwise direction. The inner ends of the shafts 23 projectbeyond the ends of hollow shafts 2! within the cabin and are providedwith arms 2'! attached to cables 28 or 23a which wind over pulleys 29suitably supported upon the bondola structure. Because the vanes 22,unlike the blades 20, serve to ut lize the force of the slipstream tounbalance the helicopter laterally and to tilt it and the rotor in thedesired direction of flight, these vanes must be operated in pairs, eachpair comprising the two vanes upon diametrically opposite sides of thegondola. That is, each pair of vanes is capable of moving the helicopterat right angles to the d rection of the other pair so that by suitablyadjusting the pairs of vanes relative to the slipstream the component ofthe forces acting on the vanes may be so directed as to cause thehelicopter to tilt, and hence travel, in any desired direction while inflight.

The steering control for operating the cables 25 and 23, and throughthem the blades 25) and vanes 22, comprises the upright tubular stick 12located in front of the pilots seat in the passenger cabin. The lowerend of the stick is branched so as to form a pair of arms 35] whichbridge a hollow shaft 3| journaled for oscillatory movement in bearings32 supported upon the gondola structure. The arms are pivotallyconnected to a pin 33 extending radially across the shaft 3| and havingits ends projecting beyond the circumference of the shaft so as to bereceived within eyes formed in the arms. A segmental guide td having itsends connected to a pair of trunnions 35 arches upwardly and freelypasses through slots 36 formed in the hollow stick. The trunnions 35 arelocated in line on opposite sides of the shaft 3! and at right-anglesthereto, and are rotatably journaled in bearings 31 fixedly secured tothe helicopter structure. By virtue of this construction, the stick iscapable of being rocked toward and from the pilot upon the pin 33 soasto rotate the trunnions 35, and also it may be rocked to the right orleft in order 4 to rotate the hollow shaft 3 l; or the stick may be sodisplaced as to describe a combination of such movements.

A pair of lugs 38 are provided on the circumference of hollow shaft 3|and located in spaced relation upon opposite sides of the stick [2; andsimilarly 1ugs 39 are provided upon the trunnions 35. Each of these lugsis connected to one of the endless cables 28 or 28a winding over thepulleys 29 and fastened to the arm 21 of one of the four vane-supportingshafts 23. As diagrammatically shown in Fig. 4, movement imparted to thehollow shaft 3| by reason of rocking the stick I2 to the right or leftwill transmit a pull through the cables 28a to swing the vanes 22 whichare located fore and aft of the gondola in the same direction and tothesame extent. In the same manner, rocking of the stick forward orbackward will rotate the trunnions 35 so as to shift the cables 23 toadjust the positions of the vanes 22 located on opposite sides of thegondola.

In order to position the torque-stabilizing blades 2%, a rod M ismounted so as to extend longitudinally within the hollow stick [2, andupon its end which projects beyond the upper end of the stick is secureda wheel 42 serving both as a hand grip for the pilot as well as a meansfor turning the rod. Coupled through a universal joint 13 to the lowerend of the rod is a stub shaft 44 which projects freely through anopening in the wall of the, hollow shaft 3| and is supported at itslower end for rotation within a bracket Ma. A spool 45 is keyed to thestub shaft and upon this spool is wound the endless cable 25 whichextends over the pulleys 26 and leads back to the spool in oppositedirections through the hollow shaft 3|. The cable 25 is connected to thearms 24 associated with each of the blade-supporting shafts 2| so thatby rotating the rod in either direction, a pull is transmitted throughthe cable 25 to the arms 24 to simultaneously adjust the position of thefour blades 2i located about the gondola in the same clockwise orcounterclockwise direction, and. to the same extent. For maintaining theblades in adjusted position, a releasable latch 46 is provided upon theupper end of the stick [2 conveniently adjacent the wheel 42 whereby thewheel may be locked to the stick after the correct trimming of theblades has been attained.

The operation of the helicopter just described is as follows: When thehelicopter is at rest on the ground it will be supported on the tricyclelanding gear H in upright position with its longitudinal axis extendingvertically, as illustrated in Fig. 1. With the vanes 22 disposed inneutral (or vertical) position, the motor will be speeded up to causethe rotor to lift the helicopter off the ground and raise it verticallyinto the air. Then, by turning the wheel 42 of the steering control l2,the blades 20 will be adjusted to an angle such as to counteract thetorque of the rotor and arrest any tendency of the gondola to rotateabout its longitudinal axis. The proper trim of the blades 20 havingbeen attained, ordinarily no further adjustments will be required solong as the speed of the rotor remains the same, and the blades may belocked in position by means of the latch 45 on the steering wheel.

Steering of the helicopter in flight is accomplished solely by means ofthe stick l2. By moving the stick forward or backward, or to the rightor left, or by a combination of such movements, the appropriate vanes 22will be rotated in a manner which has already been explained enemas isoass :to :mtercept ticker-slipstream :and :cause :the iorce :of T'the'sslipstream :acting con the wanes to tilt the :heiicoptier zand irotor:in the desired edi- "rectioneof travel. .Eozgndnrward tlreqcilotipusheszthe $116k forward; rto ago aft :he z'pulls ztl-re :sti'ck zimthenppositerdirection. :If The idesireszto goitottheiright:orlleftirhe'trocka.the:stick:inithat direc- ,tion.

"virtue :of i-the :blades :29 which :serve :for :torque :coritrol sandfthe'yanes s22 which :serve f or :directionalrontrolsthe :conditionstgoverning the :stabilityzand forward movement of .;theihelicopter,whichsconditionsrare largelyindependent o'f each other, maybeiseparatelyccontrolied:a sin mle andnatural manner onthe part of thepilot and Without-involving anunibersome and complicated constructionf.Eurthermore, because of their coincident axes of rotation,'the bladesand vanes same :each mositionedsso as :to transmit the acting force ofthe slipstream directly to'ithe gondola without interfer'mg with itheaotioniof the companion control member.

Thegondola will be suit-ably balanced so that its center of gravity-will liesuiliciently'near =its lower en'd as toprovide for stableequilibrium "while on "the ground and in the air, lhis is essential *in-'order 'to avoid 'the possibility of the "helicopter "nosing over under"the unbalancing notion produced by i the vanes "or under *the influenceof hea-vy -winds. To this end, therefore, it may be found desirable,especially in relatively light-weight helicopter constructions, to mountthe motor or fuel and oil supply, or all of them, in the bottom of thegondola in the space herein shown as reserved for the cargo compartment.

While the invention has been described in connection with a helicopteremploying one rotor, it is within the scope of the invention to employadditional rotors mounted for rotation, usually in opposite directionsso as to cancel their torques, about a common axis. The pitch of therotor blades may be made variable, as is already known in helicopterconstruction. Also, pontoons may be substituted for the wheels l8 of thelanding gear when the helicopter is intended for use ovr bodies ofwater.

Various other changes in construction, arrangement and design will occurto one skilled in the art and may be made in the preferred form of myhelicopter as described above without departing from the spirit of myinvention as defined by the following claims.

I claim:

A helicopter of the general type including a pilot-enclosing gondolahaving a vertically-disposed longitudinal axis and having downwardly andoutwardly flared side Walls, a sustaining rotor mounted above saidgondola with its axis of rotation in line with the longitudinal axis ofthe gondola, a series of approximately equidistantly spaced-apart bladesprojecting outwardly from the circumference of the gondola forofisetting the torque of the rotor, vanes mounted outwardly of and inlaterally-arranged relation with reference to the blades for providingdirectional control, the blades and vanes being arranged in pairs andthe blade and vane of each pair being mounted for pivotal movement uponsubstantially aligned axes and control means for selectively andindependently adjusting either the blades or the vanes about theirpivotal axes.

2, A helicopter of the general type including a pilot-enclosing gondola,having a vertically-disposed longitudinal axis and having downwardly andoutwardly flared side walls, a sustaining rotor mountedzabovei'saidsgondola withzits i'axis :of 51:0- .tation :line with the longitudinalaxis :of the gondola, :a series -;of riaterallyaextending blades.mounted-Qupon :the 5 gondola :approximately :equidistantly spaced aparttthereaboutfior offsetting theztorqueroiithe:rotor,ivanestmounted:outwardly of rand:inilaterallyarranged:treiation with :reference ito:the ibladesifor providing directional con trol and operating :mean's.fo-rrselectively :adjustingisaid vanes, said operating :meanscomprising a con'trol :stick imountedifor universal rocking movement,ia'plurality of cable-actuatingmembers connected :for :rota'tion to ithecontrol tstick :selectively responsive totmovement of the stick inidifierent directions, vane-supporting shafts extending'throughttheenclosing Wall of the gondola and a cablesextendingbetweenieach of 'saidcable actuating members :and vanee'supporting shafts.

-3. 'A he'licopter of the general" typeiincluding'a pilot-enclosinggondola having :a verticallysdisposed longitudinal axis and Shavingdownwardly and outwardly "flared -side 'walls, 'a sustaining rotormounted above '-said gondola wwi.th1its axis of rotation in line withthe longitudinaliaxisaof the=gondolaga series of laterally-extendingblades mounted upon the gondola approximately equidistantly spa'c'e'dapart thereabout ifOl offsetting the torque of the roton vanes mountedoutwardly of and in laterally-arranged relation with xreference to theblades for providing directional control and operating means forselectively adjusting said vanes, said operating means comprising acontrol stick mounted for universal rocking movement, a plurality ofcable-actuating members connected for rotation to the control stick andselectively responsive to movement of the stick in different directions,vane-supporting shafts extending through the enclosing wall of thegondola and a cable extending between each of said cable-actuatingmembers and vane-supporting shafts, said cables being arranged in pairsand the cables of each pair being simultaneously operable for moving apair of Vanesupporting shafts in unison.

4. A helicopter of the general type including apilot-enclosing gondolahaving a vertically-disposed longitudinal axis and having downwardly andoutwardly flared side walls, a sustaining rotor mounted above saidgondola with its axis of rotation in line with the longitudinal axis ofthe gondola, laterally-extending blades mounted upon the gondola forofisetting the torque of the rotor, vanes mounted outwardly of and inlaterally-arranged relation with referenee to the blades for providingdirectional control and operating means for selectively adjusting saidvanes and for unitarily rotating said blades, said operating meanscomprising a hollow control stick mounted for universal rockingmovement, a plurality of cableactuating members connected for rotationto the control stick and selectively responsive to movement of the stickin different directions, vanesupporting shafts extending through theenclosing wall of the gondola, a cable extending between each of saidcable-actuating members and vane-supporting shafts, a rotatable rodextending longitudinally through the hollow control stick, a hand gripconnected to said rod for rotating the rod, a spool mounted upon saidrod, a plurality of blade-supporting shafts extending through theenclosing wall of the gondola and a cable extending around the sheaveand connected to each of said blade-supporting shafts.

5. In a helicopter of the class described having laterally-disposedtorque-stabilizing blades and directional control vanes, a controlmechanism for adjusting the positions of said blades and vanes abouthorizontal axes, said mechanism comprising a hollow control stickpivotally mounted upon a hollow tube for rocking movement in a planeextending lengthwise of the tube, trunnio-ns mounted upon opposite sidesof the tube and in line with each other and with the pivoted axis of thestick, a segmental member bridging the opposed ends of the trunnions andpassing through a slot in the stick, said tube and trunnions beingsupported for oscillating movement, a rod extending lengthwise throughthe stick, a hand-grip secured to the upper end of the rod projectingabove the upper end of the stick, means for releasably locking the rodto the stick, a stub shaft universally coupled to the lower end of therod and extending through the tube, a spool mounted upon a portion ofthe.

stub shaft located within the tube and adapted to have a blade-operatingcable wound thereon, and means on each trunnion for connecting avane-operating cable thereto.

6. A helicopter of the general type including a pilot-enclosing gondolahaving a vertically-disposed longitudinal axis and having downwardly andoutwardly flared side walls, a sustaining rotor mounted above saidgondola with its axis of rotation in line with the longitudinal axis ofthe gondola, laterally-extending blades mounted upon the gondola, foroffsetting the torque of the rotor, vanes mounted outwardly of and inlaterally-arranged relation with reference to the blades for providingdirectional control and operating means for rotating companion vanes andblades about a common axis for adjusting their angular position relativeto the slipstream of the rotor, said operating means comprising hollowbladesupporting shafts extending horizontally through the enclosing Wallof the gondola, vane-supporting shafts extending through the hollowshafts and a control stick for rotating said inner and outer shaftsindependently of each other.

EL'DEN L. KIRCI-IOFF.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,191,501 Dees July 18, 19161,350,982 Beurrier et a1 Aug. 24, 1920 1,739,703 Winterkorn Dec, 17,1929 1,786,576 Nelson Dec. 30, 1930 2,058,673 Fr Oct. 27, 1936 2,074,805Platt Mar. 23, 1937 2,308,802 Barling Jan. 19, 1943

